利用MQ实现mysql与elasticsearch数据同步

流程

1.声明exchange、queue、RoutingKey

2. 在hotel-admin中进行增删改（SQL），完成消息发送

3. 在hotel-demo中完成消息监听，并更新elasticsearch数据

4. 测试同步

1.引入依赖

<!--amqp-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-amqp</artifactId>
</dependency>

我这里的mq是挂在了docker上，虚拟机地址是192.168.116.128。到时候这个根据自己的项目改就行

 spring: 
  rabbitmq:
    host: 192.168.116.128 # 主机名
    port: 5672 # 端口
    virtual-host: / # 虚拟主机
    username: itcast # 用户名
    password: 123321 # 密码

2.声明交换机、队列和绑定关系

package cn.itcast.hotel.constants;

public class MqConstants {

    /**
     * 交换机
     */
    public final static String HOTEL_EXCHANGE = "hotel.topic";
    /**
     * 监听新增和修改的队列
     */
    public final static String HOTEL_INSERT_QUEUE = "hotel.insert.queue";
    /**
     * 监听删除的队列
     */
    public final static String HOTEL_DELETE_QUEUE = "hotel.delete.queue";
    /**
     * 新增或修改的RoutingKey
     */
    public final static String HOTEL_INSERT_KEY = "hotel.insert";
    /**
     * 删除的RoutingKey
     */
    public final static String HOTEL_DELETE_KEY = "hotel.delete";
}

在hotel-demo中，定义配置类，声明队列、交换机：

package cn.itcast.hotel.config;


import cn.itcast.hotel.constants.MqConstants;
import org.springframework.amqp.core.Binding;
import org.springframework.amqp.core.BindingBuilder;
import org.springframework.amqp.core.Queue;
import org.springframework.amqp.core.TopicExchange;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MqConfig {
    // 定义交换机
    @Bean
    public TopicExchange topicExchange(){
        return new TopicExchange(MqConstants.HOTEL_EXCHANGE,true,false);
    }
    // 定义队列
    @Bean
    public Queue insertQueue()
    {
        return new Queue(MqConstants.HOTEL_INSERT_QUEUE,true);
    }
    @Bean
    public Queue deleteQueue()
    {
        return new Queue(MqConstants.HOTEL_DELETE_QUEUE,true);
    }

    // 定义绑定关系
    @Bean
    public Binding insertQueueBinding()
    {
        return BindingBuilder.bind(insertQueue()).to(topicExchange()).with(MqConstants.HOTEL_INSERT_KEY);
    }
    @Bean
    public Binding deleteQueueBinding()
    {
        return BindingBuilder.bind(deleteQueue()).to(topicExchange()).with(MqConstants.HOTEL_DELETE_KEY);
    }
}

3.发送MQ消息

在hotel-admin中的增、删、改业务中分别发送MQ消息,具体怎么添加根据：

    // 新增
    @PostMapping
    public void saveHotel(){
        //数据库新增操作
        rabbitTemplate.convertAndSend(MqConstants.HOTEL_EXCHANGE,MqConstants.HOTEL_INSERT_KEY,hotel.getId());
    }

    // 更新
    @PutMapping()
    public void updateById(){
            //数据库修改操作
            rabbitTemplate.convertAndSend(MqConstants.HOTEL_EXCHANGE,MqConstants.HOTEL_INSERT_KEY,hotel.getId());

    }
    // 删除
    @DeleteMapping("/{id}")
    public void deleteById() {
		// 数据库删除操作
        rabbitTemplate.convertAndSend(MqConstants.HOTEL_EXCHANGE,MqConstants.HOTEL_DELETE_KEY,id);

    }

4.监听MQ消息

接收MQ消息

hotel-demo接收到MQ消息要做的事情包括：

• 新增消息：根据传递的hotel的id查询hotel信息，然后新增一条数据到索引库
• 删除消息：根据传递的hotel的id删除索引库中的一条数据

1）首先在hotel-demo的cn.itcast.hotel.service包下的IHotelService中新增新增、删除业务

void deleteById(Long id);

void insertById(Long id);

2）给hotel-demo中的cn.itcast.hotel.service.impl包下的HotelService中实现业务：

@Override
public void deleteById(Long id) {
    try {
        // 1.准备Request
        DeleteRequest request = new DeleteRequest("hotel", id.toString());
        // 2.发送请求
        client.delete(request, RequestOptions.DEFAULT);
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
}

@Override
public void insertById(Long id) {
    try {
        // 0.根据id查询酒店数据
        Hotel hotel = getById(id);
        // 转换为文档类型
        HotelDoc hotelDoc = new HotelDoc(hotel);

        // 1.准备Request对象
        IndexRequest request = new IndexRequest("hotel").id(hotel.getId().toString());
        // 2.准备Json文档
        request.source(JSON.toJSONString(hotelDoc), XContentType.JSON);
        // 3.发送请求
        client.index(request, RequestOptions.DEFAULT);
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
}

编写监听类

package cn.itcast.hotel.mq;

import cn.itcast.hotel.constants.MqConstants;
import cn.itcast.hotel.service.IHotelService;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component
public class HotelListener {
    // 专门用于消息监听的类

    @Autowired
    private IHotelService hotelService;

    @RabbitListener(queues = MqConstants.HOTEL_INSERT_QUEUE)
    public void listenHotelInsertOrUpdate(Long id)
    {
        hotelService.insertById(id);
    }

    @RabbitListener(queues = MqConstants.HOTEL_DELETE_QUEUE)
    public void listenHotelDelete(Long id)
    {
        hotelService.deleteById(id);
    }
}